Vol 85: An Account of the Trigonometrical Survey Carried on in the Years 1791, 1792, 1793, and 1794, by Order of His Grace the Duke of Richmond, Late Master General of the Ordnance. By Lieut. Col. Edward Williams, and Capt. William Mudge, of the Royal Artillery; And Mr. Isaac Dalby. Communicated by the Duke of Richmond, F. R. S.